"Prepared by Sandia Laboratories, Albuquerque, New Mexico 87185 and Livermore, California 94550 for the United States Department of Energy under Contract DE-AC04-76DP00789."

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dc.description.abstract

The Hawaiian lava lake in the Kilauea Iki pit crater, resulting from the 1959 summit eruption of Kilauea volcano, has served as a natural laboratory for the continuing study of the petrology, rheology, and thermal history of ponded molten basalt flows in the field environment. During 1975 and 1976, a series of electromagnetic and seismic experiments were coordinated in an attempt to define the in-situ geophysical properties and the configuration of the molten lava core as closely as possible. Drilling and geophysical experiments in 1976 suggested that the solidified crust of the lava lake had a cool, resistive surface layer, undersaturated with water to a depth of 5 meters. A warm, wet layer containing appreciable water and/or steam was essentially isothermal (100/sup 0/C) to 33 meters. From 33 to 45 meters the temperature climbed rapidly (from 100/sup 0/ to 1070/sup 0/C) until a thin plexus of molten sills was encountered, interbedded with solid layers. Below this (50 meters) was apparently a layer having the highest temperature, lowest viscosity, and lowest density of olivine phenocrysts. At 70 meters, a transition zone to a crystalline mush was indicated, and finally (between 80 and 95 meters), solid basalt extended down to the preflow surface at a depth of 115 to 120 meters.